The invention relates to a switch to be mounted on a design element in the passenger compartment of a motor vehicle. The switch according to the invention is characterized by a simple secure assembly process as well as by its significant lack of dependence on the design of the haptic element.
By haptic element it is meant, a structural group of the switch which contains the mechanical operating elements required for manually operating the switch. The haptic element can furthermore serve as a visual element, e.g. by suitably configuring the haptic element it is possible to make the function of the switch visible to the user.
From DE 197 38 656 A1 a switch is known whose electrical or electronic switch elements and whose associated operating elements in the haptic element are positioned independently of each other on various parts of the vehicle door. The switch elements and haptic element only come into active connection after they have been fitted together. The drawback here however is that it is necessary to ensure a very close tolerance of the parts which support the switch element and haptic element, which are to be connected together, otherwise faulty positioning may have to be taken into account. DE 43 13 030 A1 and U.S. Pat. No. 5,805,402 describe groups of switches based on flexible printed conductors. They consist essentially of electrical switch elements which can preferably be used in vehicles having a flexible foil touch panel or separate operating elements held in a console. Even with this technical solution bringing together the electrical switch elements and the haptic element requires considerable effort and great care. Furthermore, switch blocks of this kind considerably restrict the freedom of design since the geometrical arrangement of the individual switch elements determines the positioning of the operating elements of the haptic element. With many design specifications, such as are customary in the automotive industry, there is a great degree of variation in the foil-bound switch elements, unless one always proceeds from the variation having the highest design specification and does not connect up the corresponding switches where the design specifications are lower. However, this leads to an undesirably high use of resources.
The object of the invention is to provide a switch to be mounted on a design element in the passenger compartment of a motor vehicle, for example on the inner trim of a door, which is cost-effective to manufacture and which can be fitted simply and securely and which can be adapted to any desired design.
According to this, the zones of the flexible conductor which support the switch elements, and the zones or operating elements of the haptic element which are associated with these zones are designed so that the relevant zones can be positioned and fixed relative to each other and can be detached from each other. Furthermore, these zones have no means for establishing a permanent electrical circuit connection. Thus, no permanent electrical contact is produced between the zones on the two sides. The term xe2x80x9celectricalxe2x80x9d and xe2x80x9celectronicxe2x80x9d switch elements includes electro-magnetic and electro-optical switch elements.
According to a variation of the invention it is hereby proposed that the haptic element cannot be brought into an electrically conductive connection with the switch elements, i.e. the haptic element has no electrically conductive component parts which can be coupled electrically with the switch elements.
According to another variation of the invention the haptic element can only be brought into electrically conductive connection with the switch elements by actuating an operating element of the haptic element whereby the electrically conducting connection only exists for as long as the switch is located in the switching state produced by actuating the operating element (xe2x80x9cswitch closedxe2x80x9d). With this variation of the invention, the haptic element has no electrical structural elements in the narrower sense (such as e.g. a resistance, a transistor, etc.), but only a contact bridge in the form of a simple electrical conductor with which an electrical connection can be established between two switch elements.
According to a preferred embodiment of the invention, the relevant zones of the conductor and haptic element are formed as mechanical plug connectors wherein a base member of the haptic element has a socket zone, such as e.g. a plug opening with which the zone of the flexible conductor supporting the switch elements can be brought into positive keyed engagement. To this end, the zones of the flexible conductor supporting the switch elements has a mechanical reinforcement element in the form of a frame around the edges, a plate at the back or a cast element incorporating the relevant zone.
A cast element is suitable when using contactless switch systems, such as magneto-resistive sensors or inductive and capacitive close-range approach sensors. The cast element thereby offers, in addition to good protection against mechanical damage, also excellent protection against chemical attack and obviously against dampness. This in turn guarantees that the switch has a high reliability and long service life.
Through suitably configuring the reinforcement element which is connected to the flexible conductor, and also the close-fitting corresponding socket opening in the haptic element, the plug connection can only be established in the proposed position. Forming the reinforcement element, whether it is by sticking a plate onto the reverse side of the conductor or by injection molding a frame round the edge of the conductor or by casting the end region of the conductor, can be undertaken with high precision and efficiency by automated machines.
The mechanical reinforcement elements can also have detent elements for securing the insert position with regard to the haptic element, as well as means for sealing the plug-in zone against dampness. When manufacturing such components it is possible to use twin component plastic injection molding technology so that it is easier to meet the demands required for a seal through the softer of the two plastics.
A further embodiment of the invention proposes designing the zones of the flexible conductor, supporting the switches, and the associated zone of the haptic element as a clamp-fit connection whereby a base body of the haptic element has a socket zone and a fixing element connectable therewith so that the zone of the flexible conductor supporting the switch elements can be clamped between the socket zone of the haptic element and the fixing element. This can be undertaken for example by a fixing element which is connected in one piece with the base body through a film hinge of a plastic base body of the haptic element. After the corresponding zone of the flexible conductor has been supplied to the socket zone of the base body, the fixing element can be swivelled towards the socket zone until its position is secured through detent elements and the conductor is thereby fixed with the switch elements relative to the position of the operating elements.
A further development of this embodiment proposes using a separate clamping plate as the fixing element. In this case the clamping plate should be provided with positive locking elements (e.g. studs) which are associated with matching detent openings (preferably around the edge) of the flexible conductor. These positive locking elements can be arranged so that only an exact positioning is possible between the clamping plate and conductor. The clamping plate is then fixed on the base body of the haptic element by means of a snap-fitting connection.
Basically all types of switch elements can be used if they are suitable for fitting flexible printed conductors. These can be formed, for example, as electrical contact faces which are allocated an electrical contact bridge which is connected to an operating element of the haptic element and closes the electric circuit when the operating element is actuated. Apart from the inductive and capacitive close-range approach switches and magneto-resistive structural elements (e.g. Hall element) already mentioned and which are each assigned a ferro-magnetic metal plate or a permanent magnet connected to an operating element of the haptic element, boxed switch elements are also suitable in the form of SMD (Surface-Mounting Device) switches or switch mats. Furthermore, transponder readers are also suitable as switch elements. Which type of switch is selected by the technician depends decisively on the technical requirements in each individual case.
At this point it should be pointed out that non-electrical principles can be used. By way of example, the switch elements provided on the flexible conductor can be formed as passive or active optical elements which are assigned on the side of the operating elements of the haptic element means for reflection for the purpose of establishing an optical transmission path or means for interrupting an optical transmission path. Further processing of the switch signal is undertaken through the interposition of an opto-electrical converter.
Next to the switch elements there are, where necessary, further structural elements such as for example an optical element for lighting up the switch, a micro controller, resistances, diodes or the like.
The invention utilizes the principle of the plug connection in order to establish in a simple reliable way an active connection between the switch elements and the operating elements of the haptic element without using at the same time (permanent-acting) electrical cable connections which are liable to breakdown. The configuration of the zones of the flexible conductor supporting the switch elements is entirely secondary to the configuration of the haptic element while simultaneously reducing the variety of designs on the switch side. i.e., by means of the technical solution according to the invention (theoretically) any number of geometric arrangements of the operating elements of the haptic element can be fitted with only one variation of cable harness.